Immune modulating compounds from fungi

ABSTRACT

The present invention relates to compositions comprising polypeptides and polysaccharides. The compositions are in general immune modulating. The invention also discloses methods of producing these compositions using filamentous fungi cultivated in liquid medium. The compositions are useful for example in the treatment of immune compromised conditions.

All patent and non-patent references cited in the present application, are hereby incorporated by reference in their entirety.

FIELD OF INVENTION

The present invention relates to immune modulating compounds comprising polysaccharides that may be isolated from a liquid culture of fungi.

BACKGROUND OF INVENTION

It is known that health-promoting effects are attributed to glucans from fungi and yeasts. “Shiitake” fungus (i Lentinus edodes) has been attributed effects which can be exploited for many medicinal purposes such as immunestimulation, anti-virus, anti-tumour, etc. Studies of lentinan have shown that it stimulates the immune system of the host in a variety of ways, such as activation of T helper cells, increased production of Interleukin 1 and Interleukin 2, increased antibody production in various forms of cancer, and decreasing the cholesterol level in the blood. (Herbs for Health, January/February, 1997; K. Jones, “Shiitake: Medicine in a mushroom”, p. 40-50, 54; Anticancer Res, Vol. 17(4A). 1997; H. Matsouka, “Lentinan potentiates immunity and prolongs the survival time of some patients”, p. 2751-2755; Adv Appl Microbiol, Vol. 39, 1993: S. C. Jong, “Medicinal and therapeutic value of the shiitake mushroom”, p. 153-184, Int J Immunopharmacol, Vol. 14, 1992; K. Irinoda, “Stimulation of microbiocidal host defence mechanism against aerosol influenza virus infection by lentinan, p. 971-977., Jpn J Cancer Res, Vol. 76(1), 1985; D. Herlyn, “Monoclonal antibody-dependent murine macrophage-mediated cytotoxicity against human tumors is stimulated by lentinan, p. 37-42).

One active ingredient of Lentinus edodes is termed lentinan, a polysaccharide based compound described as a beta-(1,3) glucan backbone with beta-(1,6) side chains.

“Solid-state” reactors are routinely used for culturing fungi such as Lentinus edodes. This is a technology which is used for many purposes such as composting, production of biological products such as enzymes, soy sauce, acetic acid, and the like. For the production of lentinan, Lentinus edodes can be cultivated on a suitable solid matrix provided by stems of tree or chips of wood to which is often added chemical compounds supporting the growth of mycelium and development of the fruiting bodies, where most of the lentinan is localised. The fruiting bodies are harvested, either by hand or mechanically, and are subsequently dried and ground to a powder which can be used as it is, or used in tablets, or sent for further processing such as extraction of lentinan.

A polysaccharide product prepared from Lentinus edode is commercially available as “Lentinan for injection” (Eureka Bio-Chemicals Pty, Australia). This product has some immunestimulating effect (see also the examples herein below).

The patent application WO03/020944 describes a number of methods of purifying extracellular immunestimulating compounds from fungi. In general these methods involve a precipitation step.

However, compositions with very high immunestimulating activity have not been disclosed. It is howtherefore an object of the present invention to provide novel compostions, preferably extracellular immune stimulating agents from fungi with high level of immune modulating activity.

SUMMARY OF INVENTION

The present invention discloses compositions comprising polysaccharides with significant immune modulating activity. Interestingly, the present invention discloses that the specific monosaccharide content of a polysaccharide composition is important for the immune modulating activity.

Thus it is one object of the present invention to provide a composition comprising one or more polypeptides and a mixture of polysaccharides, wherein the majority of the polysaccharides of the composition, preferably every polysaccharide has a molecular weight of at least 10,000 Da and wherein said mixture of polysaccharides comprises the monosaccharides galactose, mannose, and glucose in the ratio 1:0 to 25:1 to 50, preferably in the ratio 1:0 to 25:1 to 50.

It is a second object of the present invention to provide methods of producing such a composition, said method comprising the steps of

-   -   i) Cultivating a fungus in a liquid growth medium     -   ii) Purifying said composition from said liquid growth medium         It is a third object of the present invention to provide         pharmaceutical compositions comprising the above-mentioned         composition and pharmaceutically acceptable carrier(s) for use         as a medicament.

It is a further object of the present invention to provide methods of treatment of an individual, said method comprising the steps of administering to said individual the compositions according to the invention in an effective amount.

It is an additional object of the present invention to provide use of the compositions according to the invention in the manufacture of a medicament for treatment, optionally prophylactic treatment of an immune compromised condition of an individual in need of such treatment.

Definitions

-   Polysaccharides: the term “polysaccharide” as used herein covers     polysaccharides as well as polysaccharides containing and/or     covalently linked to peptides, polypeptides or the like, such as     proteopolysaccharides. -   Polysaccharides comprising monosaccharides: A polysaccharide is said     to comprise monosaccharides, wherein said monosaccharides are     covalently linked to form said polysaccharide. Hydrolysing a     polysaccharide will yield the monosaccharides that formed said     polysaccharide in free form. The monosaccharide content of a     polysaccharide can thus be determined by hydrolysing the     polysaccharide and measuring the presence of individual     monosaccharides. The monosaccharide content of a mixture of     polysaccharides is determined by determining the monosaccharide     content of the entire mixture. -   Ratio: A polysaccharide or a mixture of polysaccharides are said to     comprise galactose, mannose, and glucose in a given ratio, when     hydrolysation of said polysaccharide or said mixture of     polysaccharide yields galactose, mannose and glucose in said given     ratio Galactose, mannose, and glucose in the ratio 1:a to b:c to d,     means that for every part galactose, mannose is present in the range     of a to b parts and glucose is present in the range of c to d parts,     wherein a, b, c and d indicates numerical values. Thus, by way of     example a polysaccharide mixture comprising galactose, mannose, and     glucose in the ratio 1:5 to 25:1 to 50, means that for every part     galactose, the polysaccharide mixture comprises in the range of 5 to     25 parts mannose and in the range if 1 to 50 part glucose. -   Molecular weight; Every polysaccharide of a composition is said to     have a molecular weight of at least a given value, when said     composition has been purified using a filtration step resulting in a     molecular weight cut-off of said given value. Similarly, every     polysaccharide of a composition is said to have a molecular weight     within a given range, when said composition has been subjected to     one or more filtration steps resulting in a lower molecular weight     cut-off which is the lower value of the range and an upper molecular     weight cut-off which is the upper value of the range. Said     filtration step may for example be ultrafiltration, microfiltration,     ultracentrifugation or gel filtration. However, a composition     wherein every polysaccharide has a molecular weight of at least a     given value or every polysaccharide is said to have a molecular     weight within a given range may also be prepared by other methods. -   Polypeptide: the term “polypeptide” as used herein covers proteins,     peptides and polypeptides, wherein said proteins, peptides or     polypeptides may or may not have been post-translationally modified.     Post-translational modification may for example be phosphorylation,     methylation, glucosylation,

DETAILED DESCRIPTION OF THE INVENTION

Composition

The compositions according to the present invention comprise one or more polypeptides and a mixture of polysaccharides. Said polypeptides may optionally be covalently linked to polysaccharides. It is however also comprised within the present invention that said polypeptides are either not associated with said polysaccharides or that said polypeptides are associated with said polysaccharides in a non-covalent manner.

Thus the compositions comprise polysaccharides which may or may not be proteopolysaccharides, or the compositions may comprise a mixture of both.

The compositions according to the present invention are isolated or purified compositions, i.e. they have been subjected to one or more purification steps. In a preferred embodiment they have been purified from liquid growth medium of a fungal mycelium using at least one purification step comprising a size fractionation. Methods of purification are described in more detail below.

In a preferred embodiment, the composition essentially consists of polysaccharides and optionally polypeptides, more preferably the composition essentially consists of polysaccharides and polypeptides. Frequently, the composition is a liquid composition, and it is then preferred that the composition essentially consists of polysaccharides and optionally polypeptides dissolved in an aqueous solution optionally comprising salts and buffer.

The polysaccharides of the compositions of the invention preferably comprises the monosaccharides glucose, mannose and galactose. Examples of polysaccharides and polypeptides that may be comprised within the compositions of the invention include, but are not limited to, β-(1,3), β-(1,6) D-glucans, schizophyllan, grifolan, coriolan and Coriolus versicolor glycosylated polypeptides such as PSK and PSP, polypeptides associated with alpha-mannan such as KS-2, which may be isolated from Lentinus edodes, and reishi, which may be isolated from Ganoderma lucidum; glucuronoxylomannans; mannoglucans; glucomannans; galactoglucan and/or galactoglucomannans.

Fungi

In a preferred embodiment of the present invention the compositions disclosed herein have been produced by a fungus. Preferably, the compositions have been purified from the extracellular environment of a fungus. Even more preferably the fungus, preferably a fungal mycelium, has been cultivated in a liquid growth medium and said composition has been purified from said liquid growth medium.

It is thus preferred that the composition of the invention has been produced by a method comprising the steps of

-   -   i) cultivating a fungus, such as a fungal mycelium, in a liquid         growth medium, and     -   ii) isolating the composition from said liquid growth medium         By fungal mycelium is intended any fungal biomass, which can be         grown in a submerged culture. The fungal biomass may be in the         form of single hyphae, spores, aggregates of mycelium, and         partly differentiated mycelium.

The liquid growth medium may be any of the liquid growth media described herein below.

The fungus may be any fungus, preferably a fungus forming a fungal mycelium, more preferably the fungus is a filamentous fungus. Even more preferably, the fungus may be selected from the group consisting of Agaricus bisporus, Cordiceps sinensis, Flammulina velutipes, Ganoderma lucidum, Grifola frondosa, Lentinus edodes, Pleurotus ostreatus, Schizophyllum commune, Sclerotina sclerotium, Trametes (Coriolus) versicolor, Tremella fuciformis, Agaricus blazei, Agrocybe aegerita, Agrocybe cylindracea, Albatrellus confluens, Armillariella mellea, Auricularia auricula-judae, Auricularia polytricha, Collybia maracula, Cordiceps militar, Dendropolyporus umbellatus, Fomes fomentarius, Fomes pinicola, Ganoderma applanatum, Ganoderma tsugae, Hericium erinaceus, Hypsizygus marmoreus, Inonotus obliquus, Laetiporus sulphurous, Lenzites betulinus, Leucopaxillius giganteus, Lyophyllum cinerascens, Omphalina epichysium, Oudemansiella mucida, Panellus serotinus, Piptoporus betulinus, Phellinus linteus, Phellinus pini, Pholiota nameko, Pleurotus citrinopileatus, Pleurotus pulmonarius, Sarcedon asparatus, Trametes suavolens, Volveriella volvacea and Wolfiporia cocos.

Yet more preferably, the fungus is selected from the group consisting of Agaricus bisporus, Cordiceps sinensis, Flammulina velutipes, Ganoderma lucidum, Grifola frondosa, Lentinus edodes, Pleurotus ostreatus, Schizophyllum commune, Sclerotina scierotium, Trametes (Coriolus) versicolor and Tremella fuciformis.

In a very preferred embodiment of the present invention the fungus belongs to the class of basidiomycetes, such as a fungus of the genus Lentinus, such as Lentinus edodes.

Lentinus edodes deposited under IHEM 18992 with the Belgian Coordinated Collections of Microorganism (BCCM), 14 Rue J. Wytsman, B-1050 Bruxelles, Belgium, represents one preferred strain of Lentinus edodes. Further strains of Lentinus edodes are available from culture collections such as ATCC (American Type Culture Collection, P.O. Box 1549, Manassas, Va. 20108 USA), CBC (Centraalbureau voor Schimmelcultures, PO Box 85167, 3508 AD Utrecht, THE NETHERLANDS) and DSMZ (Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Mascheroder Weg 1b, 38124 Braunschweig GERMANY).

Additionally relevant Lentinus species, besides Lentinus edodes, includes Lentinus species such as; Lentinus albovelutinus G. Stev. (1964)=Rhodocybe albovelutina (G. Stev.) E. Horak (1971); Lentinus anthocephalus (Lév.) Pegler; Lentinus badius Bres.; Lentinus castoreus Fr. (1838)=Lentinellus ursinus (Fr.) Kühner (1926); Lentinus chrysopeplus Berk. & M. A. Curtis (1869)=Cyptotrama asprata (Berk.) Redhead & Ginns (1980); Lentinus cochleatus Fr.; Lentinus concinnus Pat.; Lentinus delicatus G. Stev. (1964)=Marasmius delicatus (G. Stev.) E. Horak (1971); Lentinus fasciatus Berk; Lentinus hepatotrichus Berk. (1859)=Lentinellus ursinus (Fr.) Kühner (1926); Lentinus hyracinus Kalchbr (1880)=Lentinellus ursinus (Fr.) Kühner (1926); Lentinus lepideus sensu Colenso (1891); Lentinus lepideus (Fr.) Fr. (1825)=Lentinus suffrutescens (Brot.) Fr (1825); Lentinus (1825)=Lentinus suffrutescens (Brot.) Fr. (1825); Lentinus novaezelandiae Berk. (1855)=Lentinellus ursinus (Fr.) Kühner (1926); Lentnus pulvinulus Berk. (1859)=Lentinellus pulvinulus (Berk.) Pegler (1965); Lentinus punctaticeps Berk. & Broome (1883); Lentinus punctaticeps cf. sensu Petersen, Nicholl & Hughes (1997); Lentinus pygmaeus Colenso (1887)=Lentinus zelandicus Sacc. & Cub. (1887); Lentinus sajor-caju (Fr.) Fr.; Lentinus squarrulosus Mont.; Lentinus strigosus (Schwein.) Fr. (1825); Lentinus suffrutescens (Brot.) Fr. (1826); and Lentinus tuberregium Fr.; Lentinus zelandicus Sacc. & Cub. (1887) (Ref: http://nzfungi.landcareresearch.co.nz).

Modulation of the Immune System

The compositions according to the invention are preferably immune modulating, preferably, the compositions are immune stimulating. The stimulation of the immune system can be demonstrated by e.g. increased antibody production, by activation of helper T-cells, or by increased production of interleukins such as Interleukin 1 and Interleukin 2.

Any assay known to the skilled person, which is suitable for testing whether a composition is immune modulating may be employed to test whether a composition of the present invention is immune modulating. Such an assay may be an in vitro or an in vivo assay.

One preferred assay is to test whether the composition is capable of inducing IL-1 production, such as IL1-α and/or IL1-β production. Thus, in a preferred embodiment of the invention, the composition according to the present invention is capable of inducing IL-1 production from at least one kind of IL-1 producing cells in an in-vitro assay. The cells may be any IL-1 producing cells, such as P388 mouse macrophage cells. IL-1 production may be determined using any suitable assay. In general, assays involving the use of specific IL-1 antibodies, such as specific IL1-α and/or IL1-β antibodies, are useful. Such assays may for example be Western blotting, ELISA or similar assays. The assay may be performed as described in example 4.

Because it is difficult to calibrate an IL1 assay, the assay is preferably performed using a specific composition as reference. Thus in one preferred embodiment of the present invention, the composition is capable of inducing production of at least 1.5, preferably at least 2, such as at least 4, for example at least 6, such as at least 8, for example at least 10, such as at least 15, for example at least 20, such as at least 30, for example at least 40 times more IL1-α, than the amount of IL1-α induced using the commercially available Lentinan for injection (Eureka Bio-Chemicals Pty, Little Collins Street. Melbourne 3000, Australia) in a reference experiment performed in parallel. In one preferred embodiment of the present invention, the composition is capable of inducing production of at least 1.5, preferably at least 2, such as at least 4, for example at least 6, such as at least 8, for example at least 10, such as at least 15, for example at least 20 times more IL1-β, than the amount of IL1-β induced using Lentinan for injection from Eureka Biochemicals Pty. in a reference experiment performed in parallel. Preferably, the aforementioned assays are performed as described in example 4. It is most preferred that the composition induced production of both IL1α and IL1β as described above.

In another embodiment of the invention, the composition is capable of enhancing antibody production in a mammal, when administered to said mammal. The mammal may for example be a mouse, rat, rabbit or even a human being. Preferably such an assay is performed by administering the composition to a mammal prior to and simultaneously with administration of an antigen, optionally in the presence of an adjuvant. Preferably, the composition is administered in the range of 1 to 30 days, preferably in the range of 1 to 10 days, more preferably in the range of 1 to 3 days prior to administration of the antigen. Subsequently, antibody production in the mammal may be determined. The composition is preferably capable of inducing production of at least 1.5, more preferably at least 2, even more preferably at least 2.5, such as at least 3, for example at least 4, such as 6 times more antibody compared to the amount of antibody produced without administration of the composition. An example of such an assay is outlined in example 6.

It is preferred that the composition is immune modulating in more than one assay system, such as in a combination of any of the assay systems described herein above.

Monosaccharide Content

The composition according to the present invention preferably comprises polysaccharides, wherein the majority of the polysaccharides, preferably at least 60%, more preferably at least 70%, even more preferably at least 80%, yet more preferably at least 90%, even more preferably at least 95%, yet more preferably essentially all polysaccharides, most preferably every polysaccharide has a molecular weight above 10,000 Da, preferably above 30,000 Da, more preferably above 40,000 Da, even more preferably above 50,000 Da, for example at least 100,000 Da, such as at least 300,000 Da, for example at least 1,000,000 Da. In one embodiment of the invention the majority of polysaccharides, preferably every polysaccharide of the composition has a molecular weight within the range of 10,000 to 3,000,000 Da., for example within the range of 30,000 to 3,000,000, such as within the range of 40,000 to 3,000,000, for example within the range of 50,000 to 3,000,000, such as in the range of 50,000 to 100,000, for example in the range of 100,000 to 300,000, such as in the range of 300,000, to 1,000,000, for example in the range of 1,000,000 to 3,000,000.

Preferably, the composition has been purified by a method involving at least one size fractionation step. Thus it is preferred, that the composition has been purified using at least one size fractionation step wherein molecules, such as polysaccharides with a nominal molecular weight above a given cut-off are separated from molecules, such as polysaccharides with a nominal molecular weight below said cut-off. By way of example, if the size fractionation is ultrafiltration or microfiltration a membrane with said cut-off may be used. If the size fractionation is gel filtration a gel with said molecular weight cut off may be chosen or a particular elution fraction may be used. In one embodiment of the invention the larger molecular weight fraction is used, wherein the cut-off preferably is 10,000 Da, more preferably 30,000 Da, even more preferably 40,000 Da, yet more preferably 50,000 Da.

In another embodiment of the invention, the composition has been purified by a method involving one or more size fractionation steps, wherein a resulting fraction comprises polysaccharides with a nominal molecular weight below a given cut-off and above a given cutoff. By way of example, if the size fractionation is ultrafiltration or microfiltration, then first one fractionation step using a membrane with the lower molecular weight cut off may be performed. The larger molecular weight fraction may be collected and subjected to a second ultrafiltration or microfiltration using a membrane with the upper molecular weight cut off. After the second filtration step the lower molecular weight fraction may be collected. If gel filtration is used a particular elution fraction may be used. If ultracentrifugation is used, a membrane with the lower molecular cut-off and a membrane with the upper molecular weight cut-off may be used.

The composition according to the present invention comprises a mixture of polysaccharides, wherein said mixture comprises the monosaccharides galactose, mannose, and glucose in the ratio 1:5 to 25:1 to 50. Thus, the ratio reflects the ratio within the entire mixture of polysaccharides. It is thus feasible that each individual polysaccharide within the mixture comprises a different ratio of the monosaccharides.

The ratio may in general be determined by degrading the entire mixture of polysaccharides into monosaccharides and subsequently determining the concentration of each of said monosaccharides. Polysaccharides may be degraded to their constituent monosaccharides by hydrolysis, for example by hydrolysis in a strong acid, such as HCl. The hydrolysate may be analysed by any conventional method available to the skilled person, for example by HPLC, mass spectrometry or NMR.

In one embodiment of the invention the polysaccharides comprise the monosaccharides glucose and mannose. In another embodiment of the invention the polysaccharides comprise the monosaccharides glucose and galactose. In a preferred embodiment of the invention, the polysaccharides of the composition comprise the monosaccharides galactose, mannose and glucose. However,

It is preferred that the mixture of polysaccharides comprises in the range of 5 to 25, preferably in the range of 5 to 20, more preferably in the range of 5 to 17, even more preferably in the range of 6 to 15, yet more preferably in the range of 7 to 14, such as in the range of 10 to 17, for example in the range of 11 to 16, such as in the range of 12 to 15, for example in the range of 13 to 14, such as approximately 13.4+/−0.4, for example 13.4+/−0.4 parts mannose for every part galactose.

It is preferred that the mixture of polysaccharides comprises in the range of 1 to 50, preferably in the range of 1 to 40, more preferably in the range of 1 to 30, even more preferably in the range of 1 to 25, yet more preferably in the range of 1 to 20, even more preferably in the range of 2 to 15, yet more preferably in the range of 2 to 14, such as in the range of 8 to 17, for example in the range of 9 to 16, such as in the range of 10 to 15, for example in the range of 11 to 14, such as approximately 12.6+/−1.3, for example 12.6+/−1.3 parts glucose for every part galactose.

It is even more preferred that the mixture comprises a ratio of mannose to galactose as indicated herein above and a ration of glucose to galactose in a ration as indicated herein above.

In embodiments of the invention, wherein the polysaccharides comprise mannose and glucose it is preferred that they comprise in the range of 0.1 to 30, such as in the range of 0.1 to 0.25, for example in the range of 0.25 to 0.5, such as in the range of 0.5 to 0.75, for example in the range of 0.75 to 1, such as in the range of 1 to 5, for example in the range of 5 to 10, such in the range of 10 to 20, for example in the range of 20 to 30 parts glucose for every part mannose. Preferably the polysaccharides comprise in the range of 0.5 to 2 parts glucose for every part mannose, more preferably 13.4+/−0.4 parts mannose 12.6+/−1.3 part glucose.

In a very preferred embodiment of the invention the composition comprises a mixture of polysaccharides comprises the monosacharides galactose, mannose, and glucose in the ratio 1:5 to 25:1 to 50, more preferably 1:13.4+/−0.4:12.6+/−1.3.

In another embodiment of the invention the composition comprises a mixture of polysaccharides, wherein the polysaccharides within said mixture having a molecular weight in the range of 50,000 to 100,000 comprises in the range of 3 to 15, preferably in the range of 4 to 14, more preferably in the range of 5 to 13, even more preferably in the range of 6 to 12, yet more preferably in the range of 7 to 11, even more preferably in the range of 7.9 to 9.9, for example approximately 8.9 parts mannose for every part galactose. In this embodiment it is preferred that the polysaccharides having a molecular weight in the range of 50,000 to 100,000 comprises in the range of 1 to 5, preferably in the range of 2 to 4, even more preferably in the range of 2.5 to 3.5, such as approximately 2.9 parts glucose for every part galactose. It is preferred that the polysaccharides of said composition having a molecular weight in the range of 50,000 to 100,000 Da comprise the monosacharides galactose, mannose, and glucose in the ratio 1:4 to 14:1 to 5, preferably the ratio is approximately 1:8.9:2.9.

In another embodiment of the invention the composition comprises a mixture of polysaccharides, wherein the polysaccharides within said mixture having a molecular weight in the range of 100,000 to 300,000 comprises in the range of 3 to 15, preferably in the range of 3 to 14, more preferably in the range of 3 to 13, even more preferably in the range of 3 to 12, yet more preferably in the range of 4 to 11, even more preferably in the range of 5 to 10, yet more preferably in the range of 6.3 to 8.3, for example approximately 7.3 parts mannose for every part galactose. In this embodiment it is preferred that the polysaccharides having a molecular weight in the range of 100,000 to 300,000 comprises in the range of 1 to 5, preferably in the range of 2 to 4, even more preferably in the range of 2.5 to 3.5, such as approximately 2.9 parts glucose for every part galactose. It is preferred that the polysaccharides of said composition having a molecular weight in the range of 50,000 to 100,000 Da comprise the monosacharides galactose, mannose, and glucose in the ratio 1:3 to 13:1 to 5, preferably the ratio is approximately 1:7.3:2.9.

In another embodiment of the invention the composition comprises a mixture of polysaccharides, wherein the polysaccharides within said mixture having a molecular weight in the range of 300,000 to 1,000,000 comprises in the range of 3 to 16, preferably in the range of 5 to 15, more preferably in the range of 5 to 14, even more preferably in the range of 6 to 13, yet more preferably in the range of 7 to 12, even more preferably in the range of 8.9 to 10.9, for example approximately 9.9 parts mannose for every part galactose. In this embodiment it is preferred that the polysaccharides having a molecular weight in the range of 300,000 to 1,000,000 comprises in the range of 1 to 5, preferably in the range of 2 to 4, even more preferably in the range of 2.5 to 3.5, such as approximately 3.1 parts glucose for every part galactose. It is preferred that the polysaccharides of said composition having a molecular weight in the range of 300,000 to 1,000,000 Da comprise the monosacharides galactose, mannose, and glucose in the ratio 1:5 to 15:1 to 5, preferably the ratio is approximately 1:9.9:3.1.

In another embodiment of the invention the composition comprises a mixture of polysaccharides, wherein the polysaccharides within said mixture having a molecular weight of at least 1,000,000 comprises in the range of 3 to 17, preferably in the range of 4 to 16, more preferably in the range of 5 to 15, even more preferably in the range of 6 to 14, yet more preferably in the range of 7 to 13, even more preferably in the range of 8 to 12, even more preferably in the range of 9.3 to 11.3, for example approximately 10.3 parts mannose for every part galactose. In this embodiment it is preferred that the polysaccharides having a molecular weight of at least 1,000,000 comprises in the range of 1 to 5, preferably in the range of 2 to 4, even more preferably in the range of 2.5 to 3.5, such as approximately 2.9 parts glucose for every part galactose. It is preferred that the polysaccharides of said composition having a molecular weight in the range of at least 1,000,000 Da comprise the monosacharides galactose, mannose, and glucose in the ratio 1:4 to 1:5 to 15:1 to 5, preferably the ratio is approximately 1:10.3:2.9.

Determination of the monosaccharide content of polysaccharides with a molecular weight within a given range may be determined by fractionating the composition according to size for example by ultrafiltration, microfiltration, ultracentrifugation or gelfiltration. For example this may be done as described in example 2.

Polypeptide

The composition according to the invention preferably comprises polypeptides. The term polypeptide as used herein covers both proteins, peptides and polypeptides. Said polypeptides may be in free form, they may be covalently linked to a polysaccharide or they may be non-covalently associated with a polysaccharide or a mixture of the aforementioned.

It is preferred that the composition comprises sufficient polypeptide in order to allow for oral administration of the composition. If the composition comprises too little polypeptide, then no or little immune modulation is obtained in an individual after oral administration of the composition to said individual. It is therefore preferred that the composition of the invention comprises at least 10 μg/L, more preferably at least 20 μ/L, even more preferably at least 25 μg/L, for example in the range of 10 to 1000 μg/L, such as in the range of 20 to 1000 μg/L, for example in the range of 25 to 1000 μg/L, such as in the range of 25 to 100 μg/L, for example in the range of 25 to 35 μg/L polypeptide, preferably soluble polypeptide. It is preferred that the composition comprising the aforementioned concentration of polypeptide, comprises in the range of 0.1 to 2, more preferably in the range of 0.5 to 1.5, even more preferably around 1 mg/ml polysaccharide. If the composition comprises more or less polysaccharide it is preferred that the amount of polypeptide is proportionally reduced or enhanced.

Method of Preparing the Composition

Preferably, the compositions of the invention are prepared by a method comprising the steps of

-   -   i) Cultivating a fungus in a liquid growth medium     -   ii) Purifying said composition from said liquid growth medium         Cultivating the fungus in a liquid growth medium in general         involves dissolving nutrient compounds required for growth of         said fungus in water, transferring the solution to a bioreactor         and inoculating the bioreactor with cells or spores of the         fungus, such as a fungal mycelium, or fractions thereof, to be         cultivated. This is done under sterile conditions and with         control of the environment in order to give the fungus a         suitable chemical and physical environment. Cultivating fungi in         liquid growth medium is also termed “liquid state” cultivation.

During “liquid-state” cultivation the medium with the fungal biomass is preferably agitated to reduce the occurrence of gradients and to ensure oxygen availability to the submerged cells. When fungi are grown in a bioreactor, oxygen may be supplied to the liquid medium and the level of dissolved oxygen may be controlled by known methods.

The liquid growth medium is an aqueous solution, preferably sterile water, comprising nutrient compounds. The liquid medium supports fungal growth and preferably stimulates the production of extracellular compounds, such as immune modulating agents. The liquid growth medium may comprise one or more typical ingredients required for growth of microbial organisms such as malt extract, yeast extract, peptone, glucose, sucrose, sucrose, salts providing phosphate, magnesium and potassium, corn-steep liquor and vitamins such as thiamine. More preferably, the medium comprises sucrose, corns steep liquor, phosphate and magnesium for mycelium growth and production of polysaccharides.

For inoculation of the growth medium, fungal mycelium, such as Lentinus edodes mycelium from agar plates containing for example malt extract, yeast extract, peptone and glucose can be used. Fungi can initially be cultivated on agar plates comprising the above nutrient compounds supporting the growth of the fungus. The plates are inoculated with mycelium and incubated at least until a visible growth is evident on the plates. Dependent on the fungus, this usually can take from about 7 days to about 24 days or from about 10 to 30 days, typically 14 days or up to 20 days, at a temperature in the range of from 18 to 32° C., preferably in the area of from 22 to 30° C., such as a temperature of about 23° C. to 27° C., such as around 25° C.

As an alternative to inoculation with mycelium from agar plates, inoculation of the growth medium can be carried out by using mycelium from a fermentation broth in e.g. a shake flask medium comprising nutrient compounds supporting cell growth. Shake flasks for cultivating fungal mycelium can initially be inoculated with the mycelium which is cultivated on agar plates. The mycelium is taken from the plates and transferred aseptically to shake flasks containing sterile water comprising dissolved nutrient compounds and nutrient salts supporting the growth of the fungal mycelium. A typical growth medium contains sucrose, corn steep liquor, phosphate and a magnesium. The amount of inoculation material which gives the highest production of extracellular lentinan can be selected following initial experiments.

The time for incubation of the shake flasks depends on the specific fungus. Typically, the shake flasks can be incubated by shaking for 6 to 21 days, preferably from 7 to 18 days, more preferably from 8 to 14 days at a temperature in the range of from 18 to 32° C., preferably in the area of from 22 to 30° C., such as a temperature of about 23° C., for example 24° C., such as 25° C., for example 26° C., such as 27° C., for example 28° C., such as 29° C., for example 30° C. The shake flasks may also be incubated from 8-25 days, more preferably from 10-20 days, more preferably from 12-18 days. The temperature may also be from 18 to 37° C., preferably from 23 to 32° C. such as about 25° C.

The content of the shake flasks can be used for inoculating a bioreactor. In that case, the reactor comprises a sterile solution of nutrient compounds and nutrient salts in water for mono-culture cultivation of basidiomycete fungal mycelium, or fractions thereof, such as Lentinus fungal mycelium, such as Lentinus edodes.

The bioreactor fermentation period is typically in the range of from 50 hours to 300 hours, preferably in the range of from 80 hours to 270 hours, and the temperature is kept constant in the range of 18 to 32° C., preferably in the area of from 22 to 31° C., such as a temperature of about 23° C., for example 24° C., such as 25° C., for example 26° C. such as 27° C., for example 28° C., such as 29° C., for example 30° C. The temperature may also be from 18 to 37° C., preferably from 23 to 32° C. such as about 25° C.

The reactor is fitted with an inlet for supplying air to the fermentation broth, and the fermentation broth is preferably kept under continuous agitation either as a result of the addition of air, or by means of a mixer device suitable for providing a good mixing of the content of the reactor.

It is preferred to adjust the pH of the growth medium to from about 3 to about 7, such as a pH of from about 4.5 to about 6.5, for example a pH of about 6, before the growth medium is inoculated with fungal mycelium, or fractions thereof, such as L. edodes mycelium. After the initial adjustment, pH may be dropped naturally during the course of the fermentation, or controlled at a particular value in the range pH 3 to 7, using addition of suitable pH-control agents, such as acid and base. The temperature of the growth medium is preferably in the range of from 18 to 32° C., preferably in the area of from 22 to 31° C., such as a temperature of about 23° C., for example 24° C., such as 25° C., for example 26° C., such as 27° C., for example 28° C., such as 29° C., for example 30° C. The temperature may also be from 18 to 37° C., preferably from 23 to 32° C. such as about 25° C.

Samples can be obtained from the bioreactor and analysed for biomass, metabolic products and nutrient compounds, the determinations of which can assist the operator of the bioreactor in the running of the fermentation process. Typical analyses routinely carried out are determination of biomass, residual sugar concentration and extracellular polysaccharide concentration. A person skilled in the art knows the methods for analysis which can be employed in this respect.

Preferably, the method for preparing the compositions according to the invention involves a step of purifying the extracellular fraction of the liquid growth medium from the fungal mycelium. The extracellular fraction of the liquid fermentation medium is also termed the supernatant and this fraction can be separated from the fungal mycelium by e.g. centrifugation or filtration, or indeed by any other means available for obtaining a liquid fraction essentially without any fungal mycelium present therein. The term “essentially without any fungal mycelium present therein” shall denote that the concentration of fungal mycelium, including fractions thereof, has been reduced at least by a factor of 10³, such as reduced by a factor of at least 10⁴, for example a factor of at least 10⁵, such as reduced by a factor of at least 10⁶.

In preferred embodiments of the invention the purification comprises at least one size fractionation step. Preferably, this size fractionation step is performed on the extracellular fraction. This size fractionation step may ensure that every polysaccharide of the composition has a molecular weight of at least a given value (see also herein above). The size fractionation step may be any size fraction known to the skilled person, for example ultracentrifugation, ultrafiltration, microfiltration or gelfiltration. Thus in a preferred embodiment of the invention, the composition is purified from a liquid growth medium by a method involving one or more purification steps selected from the group consisting of ultracentrifugation, ultrafiltration, microfiltration and gelfiltration. Preferably, the purification step(s) are selected from the group consisting of ultrafiltration, microfiltration and ultracentrifugation, even more preferably from the group consisting of ultrafiltration and microfiltration

Ultrafiltration is a membrane process where the membrane fractionates components of a liquid according to size. The membrane configuration is normally cross-flow wherein the liquid containing the relevant components are flowing across the membrane. Some of the liquid, containing components smaller than the nominal pore size of the membrane will permeate through the membrane. Molecules larger than the nominal pore size will be retained. The desired product may be in the retentate or the filtrate. If the ultrafiltration is performed in order to prepare a composition, wherein every polysaccharide within said composition has a molecular weight above a given value, the desired product is in the retentate. If a serial fractionation is made, the product may be in the retentate or filtrate

Microfiltration is a membrane separation process similar to UF but with even larger membrane pore size allowing larger particles to pass through.

Gel filtration is a chromatographic technique in which particles are separated according to size. The filtration medium will typically be small gel beads which will take up the molecules that can pass through the bead pores. Larger molecules will pass through the column without being taken up by the beads.

Gel-filtration, ultrafiltration or microfiltration may for example be performed as desribed in R Hatti-Kaul and B Mattiasson (2001), Downstream Processing in Biotechnology, in Basic Biotechnology, eds C Ratledge and B Kristiansen, Cambridge University Press) pp 189.

A non-limiting method of preparing the compositions according to the invention is described in example 1.

Methods of purifying extracellular agents from a liquid growth medium involving alcohol precipitation have been described. However, alcohol precipitation may reduce the immune modulating effect and compositions purified using alcohol precipitation are therefore less preferable. In one embodiment of the invention the method therefore does not involve an alcohol precipitation step, more preferably the method does not involve a precipitation step.

Pharmaceutical Compositions and Uses Thereof

Provided in another embodiment of the invention is the use of the compositions of the invention in a method for stimulating the immune system of an individual in need of such stimulation. The composition may be administered e.g. orally or subcutaneously to the individual in a pharmaceutically effective amount capable of stimulating the immune system of the individual. The stimulation of the immune system can be demonstrated by e.g. increased antibody production, by activation of helper T-cells, or by increased production of interleukins such as Interleukin 1 and Interleukin 2.

Provided in yet another embodiment of the invention is the use of the compositions of the invention in the manufacture of a medicament for treating an immune compromised condition in an individual in need of such treatment. An immune compromised condition in an individual may be demonstrated e.g. by immune system factors such as an insufficient amount of antibodies, or a decreased antibody production, by an insufficient amount of helper T-cells, or a decreased production of helper T-cells in the individual, by an insufficient amount of B-cells, or a decreased production of B-cells in the individual, by an insufficient amount of natural killer (NK)-cells, or by a decreased production of NK.cells in an individual or by an insufficient amount of interleukins such as Interleukin 1 and Interleukin 2, or a decreased production of interleukins such as Interleukin 1 and Interleukin 2 in the individual. The immune compromised condition may be any of those disclosed below. The treatment may be prophylactic, ameliorating or curative.

“Insufficient amount” and “decreased production” as used herein above shall denote such amounts and productions which a medical expert considers as being below a predetermined level or value normally associated with a healthy individual. The amount and/or production will generally depend on factors such as age, general physical condition, and the like. For this reason a predetermined level or value shall be determined on an individual basis by a medical expert. One indication of an immune compromised condition in an individual is a gradually decreasing number of antibodies, a gradually decreasing number of CD4 (positive) cells, or a gradually decreasing number of T-helper cells per unit (blood) sample volume measured over time, such as days, weeks, months or years.

In one aspect the present invention relates to pharmaceutical compositions comprising the composition according to the invention and pharmaceutically acceptable carrier(s). The pharmaceutical compositions may be prepared by conventional techniques, e.g. as described in Remington: The Science and Practice of Pharmacy 1995, edited by E. W. Martin, Mack Publishing Company, 19th edition, Easton, Pa. The compositions may appear in conventional forms, for example capsules, tablets, lozenges, powders, syrups, solutions or suspensions.

In one aspect the invention relates to a method of treatment of an individual diagnosed with an immune compromised condition, said method comprising the steps of administering to said individual the composition according to the invention or the pharmaceutical composition according to the invention in an amount effective in treating said immune compromised condition.

The administered amount may in be an amount effective in prophylactically treating said immune compromised condition.

Also provided is a method of treatment of an individual recovering from surgery or illness and at risk of contracting an immune compromised condition, said method comprising the steps of administering to said individual the composition according to the invention or the pharmaceutical composition according to the invention in an amount effective in boosting the immune system of said individual.

Furthermore a method of treatment of an individual diagnosed with or at risk of contracting acquired immunodeficiency syndrome is provided, said method comprising the steps of administering to said individual the composition according to the invention or the pharmaceutical composition according to the invention in an amount effective in treating or prophylactically treating said syndrome.

The immune compromised condition may be selected from the group consisting of an infectious disease, a parasitic disease, haemophilus meningitis, pneumococcal meningitis, streptococcal meningitis, staphylococcal meningitis, meningitis due to other organisms, encephalitis, viral pneumonia, pneumococcal pneumonia, other bacterial pneumonia, pneumonia due to other specified organisms except bacteria, bronchopneumonia, organism unspecific pneumonia, influenza, unspecified diarrhea, hepatitis unspecified, acute and subacute necrosis of the liver, chronic hepatitis, and abscess of liver.

Furthermore, the immune compromised condition may be an infectious or parasitic disease caused by, or selected from, cholera, salmonella, shigellosis, Escherichia coli, intestinal infection due to other specified bacteria, Clostridium difficile, viral gastroenteritis, infectious colitis, enteritis and gastroenteritis, infectious diarrhea, tuberculosis, listeriosis, pasteurellosis, mycobacterium, diphtheria, pertussis, meningococcus, streptococcus septicaemia, staphylococcus septicaemis, pneumococcal septicaemia, septicaemia due to anaerobes, septicaemia due to other gram-negative organisms, actinomycotic infection, gas gangrene, toxic shock syndrome, necrotizing facilitis, Friedlander's bacillus, haemophilus influenzae, pseudomonas, AIDS/HIV infections, acute poliomyelitis, Creutzfeldt-Jacob disease, subacute sclerosing panencephalitis, progressive multifocal leucoencephalopathy, unspecified slow virus infection of the central nervous system, coxsackie virus, unspecified viral meningitis, lymphocytic choriomeningitis, unspecified viral encephalitis, chickenpox, herpes zoster, herpes simplex, viral hepatitis ‘A’, viral hepatitis ‘B’, other specified viral hepatitis, chronic hepatitis, abscess/acute necrosis of liver, infectious mononucleosis, cytomegalic inclusion disease, chlamydise, adenovirus, viral infection, syphilis, candida, unspecified histoplasmosis, aspergillosis, cryptococcosis, mycoses, strongyloidiasis, intestinal parasitism, toxoplasmosis, sarcoidosis, pneumocystis carinii, post polio syndrome, haemophilus meningitis, pneumococcal meningitis, streptococcal meningitis, staphylococcal meningitis, encephalitis, pneumonia due to adenovirus, pneumonia due to respiratory syncytial virus, pneumonia due to parainfluenza virus, pneumonia due to other virus, viral pneumonia, pneumococcal pneumonia, pneumonia due to klebsiella pneumoniae, pneumonia due to pseudomonas, pneumonia due to haemophilus influenzae, pneumonia due to streptococcus, pneumonia due to staphylococcus, and bacterial pneumonia.

The individual may be a mammal including a human being.

The compositions of the invention may be administered using any suitable administration form; usually however, administration will be oral or parenteral. Oral administration in the form of a syrup comprising the composition and/or a capsule containing a syrup comprising the composition or in a powder form of the composition is preferred.

The dosage requirements will vary with the particular composition employed, the route of administration and the particular individual being treated. Ideally, an individual to be treated by the present method will receive a pharmaceutically effective amount of the compound in the maximum tolerated dose.

In general the daily oral dosage regimen may be about 0.001 to about 100 mg/kg, preferably in the range of 0.01 to 50 mg/kg, more preferably in the range of 0.1 to 10, even more preferably in the range of 1 to 2 mg/kg of total body weight. It will also be recognised by one skilled in the art that the optimal quantity and spacing of individual dosages of the composition will be determined by the nature and extent of the condition being treated, the form, route and site of administration, and the particular patient being treated, and that such optimums can be determined by conventional techniques. It will also be appreciated by one skilled in the art that the optimal course of treatment, i.e., the number of doses of the composition given per day for a defined number of days, can be ascertained by those skilled in the art using conventional course of treatment determination tests.

The composition and the pharmaceutical compositions according to the invention may also form part of a kit comprising said compositions and a dosage regime instruction with guidelines for dose and time administration.

EXAMPLES

The following examples describe illustrative embodiments of the invention and should not be regarded as limiting for the invention.

Example 1

Carbohydrate Composition

Lentinus edodes was cultivated in liquid culture in medium comprising 15 g/l glucose, 3 g/l malt extract, 3 g/l yeast extract and 5 g/l peptone in shake flasks at 25° C. After cultivation the biomass was separated from the rest of the fermentation broth by filtration. The supernatant was subjected to ultrafiltration using a membrane with a nominal pore size of 50,000 Da. The retentate (herein designated the “MediMush product”) was used for analysis of monosaccharide content.

For comparison, commercially available Lentinan for injection (Eureka Bio-Chemicals Pty, Little Collins Street. Melbourne 3000, Australia) was used in a reference experiment performed in parallel (herein after this product is designated “Eureka”).

Samples were hydrolysed to their constituent monosaccharides in 1N HCl at 100° C. The hydrolysates were analysed by HPLC using a Dionex MA-1 column with 600 mM NaOH as the mobile phase; detection was by pulsed amperometry.

The major monosaccharides of the MediMush product was mannose and glucose and some galactose. Table 1 displays the relative monosaccharide content of the MediMush product and Eureka.

TABLE 1 SAMPLE MANNOSE GLUCOSE GALACTOSE MediMush 13.4 ± 0.4 12.6 ± 1.3 1 Eureka 2.8 90.1 1

Example 2

Molecular Weight Fractionation

For molecular weight characterisation of their biological activity, the MediMush sample was centrifuged through Microsep (Pall Life Sciences) centrifugal ultrafilters at 6° C. and 7,500xg. Filters with nominal MWCO values of 50,000-1,000,000 were used. Analytical results (see table 2) showed that material yielding mannose, glucose and galactose on acid hydrolysis passed through all four MWCO membranes used:

TABLE 2 MWCO MANNOSE GLUCOSE GALACTOSE 1000000 10.3 2.9 1 300000 9.9 3.1 1 100000 7.3 2.9 1 50000 8.9 2.9 1

Example 3

Soluble Protein

Soluble protein in the samples was measured by a microscale version of the Coomassie dye-binding assay (Mousdale, D. M, Campbell, M. S., Coggins, J. R. “Purification and characterisation of bifunctional dehydroquinase-shikimate: NADP dehydrogenase from pea seedlings”. Phytochemistry 367, 217-222 (1987). The amounts of soluble protein in the two products are shown below:

SAMPLE SOLUBLE PROTEIN (μg/L) MediMush sample 31.5 +/− 3.43 Eureka product 4.5 (+/−0.6, n = 3)

Example 4

Immunostimulation

Tissue Culture

P388 cells are mouse macrophage like cells, which secrete large amounts of interleukin-1 (IL-1) when stimulated (detailed information on the cells is available from the ECACC). The amount of IL-1 secreted can be quantified using an ELISA (Enzyme-Linked ImmunoabSorbant Assay) based method and used as a measure of how stimulated the cells are. It should be noted that no absolute value exist to calibrate such an assay and it is therefore preferred that a reference sample is analysed in parallel and the IL1 production is evaluated as compared to the IL1 production induced by the reference sample. There are two forms of IL-1, IL1-α and IL-β. The P388 cells are seeded in a 12 well culture plate and allowed to grow overnight. The various stimulants are added at differing concentrations and incubated at 37° C. for 24 hr.

ELISA

50 μl of the stimulated culture medium from each well was mixed with coating buffer and aliquoted into a 96 well ELISA plate and allowed to coat overnight a 4° C. This step allows the antigen (IL-1) to bind to the surface of the ELISA plate. The IL-1 is detected using two antibodies against the two different forms of IL-1, which are raised in a goat (primary antibodies). The next step uses another antibody, which detects the goat antibody (secondary antibody). The antibody is conjugated to horse-radish perioxidase, which gives a colour reaction when substrate is added. The amount of colour measured by a spectrophotometer (ELISA reader) correlates with the amount of IL-1 present thus quantifying how stimulated the tissue culture cells are.

Results

Total Sample Assay.

The two products were tested at a range of concentrations, the optimum value was found to be 50 μg/ml for IL1α and 100 μg/ml for IL1β. Results are given in table 3.

TABLE 3 Sample MediMush product Eureka product IL1α 0.173 ± 0.033 0.003 IL1β 0.168 ± 0.053 0.016

The MediMush product was markedly immunostimulatory. The Eureka product showed some immunostimulation but was significantly weaker than the MediMush product. The MediMush product induced production of 58 times more IL1α and 20 times more IL1-β than Eureka.

Assay of Fractions

The filtrate was tested so that molecules greater than the filter cut off would not be present in the assay. The results are presented as absorbances and give only a relative immunostimulatory indication. No absolute value exists to calibrate such an assay.

TABLE 4 Filtrate MWt IL1α Nominal Mwt less than: stimulation IL1β stimulation 1,000,000   3,000,000 0.082 0.073 300,000   900,000-1,800,000 0.086 0.040 100,000 300,000-900,000 0.07 0.071  50,000 150,000-300,000 0.086 0.066

All filtrate materials showed significant immunostimulation.

Example 5

In order to compare two different production methods, the immune stimulating activity of the MediMush product prepared as described in example 1 was compared to the immune stimulating activity of a polysaccharide composition, which had not been subjected to size fractionation.

This product was prepared by cultivating Lentinus edodes in liquid culture as described in example 1. To the supernatant thus obtained around 2 volumes of absolute ethanol was added to precipitate the product. The precipitate was removed, washed with absolute ethanol and re-suspended in distilled water.

The immune stimulation assay was performed as described in example 4. The results using the MediMush product is given in table 5 and the results using the precipitated product are given in table 6.

TABLE 5 Sample MediMush product Eureka product IL1a 0.173 ± 0.033 0.003 IL1b 0.168 ± 0.053 0.016

TABLE 6 Sample Precipitated product Eureka product IL1a 0.166 0.023 IL1b 0.159 0.078

The assays were not performed in parallel and the numerical values obtained can therefore not be compared. However, since Eureka was used as a reference in both studies, the results may be compared as fold enhancement compared to Eureka. These values are given in table 7 below. As is apparent, both compositions were significantly more immune stimulating than Eureka. However, the MediMush product was more immune stimulating than the precipitated product.

TABLE 7 Sample MediMush: Eureka Precipitated product: Eureka IL1a 57.67 7.22 IL1b 19.69 2.04

Example 6

For a determination of immunostimulating characteristics, the following method may be used: 12 weeks old Sprague Dawley rats receives 1 mg of the composition according to the invention in 0.5 ml 0.09 saline (i.p.) 2 days before the immunisation. Control animals receives 1 mg casein. The animals are immunised with BSA (0.5 mg) in 0.25 “Freunds Complete Adjuvant” and blood samples are obtained after 11 days for measurement of the antibody response. The specific anti-BSA antibody concentration is determined against an absolute standard of antibody BSA by means of “sandwich” ELISA. 

1. An isolated composition comprising a mixture of polysaccharides, wherein the majority of the polysaccharides of the composition have a molecular weight of at least 30,000 Da, wherein a first part of said polysaccharides have a molecular weight of from 30,000 Da to 1,000,000 Da, wherein a second part of said polysaccharides have a molecular weight of at least 1,000,000 Da, wherein essentially no polysaccharides have a molecular weight of less than 30,000 Da, wherein said mixture of polysaccharides comprises the monosaccharides galactose, mannose and glucose in the ratio 1:0.033 to 500:1 to 50, and wherein the composition is produced by a method comprising the steps of a) cultivating a fungus of the genus Lentinus in a liquid growth medium under appropriate conditions to provide a suitable chemical and physical environment supporting the growth of a fungus of the genus Lentinus in a liquid growth medium, and b) isolating the composition from said liquid growth medium.
 2. The composition according to claim 1, wherein the composition is isolated from the liquid growth medium by a method involving ultracentrifugation, ultrafiltration, microfiltration or gel filtration.
 3. The composition according to claim 1, wherein said composition is immune stimulating.
 4. The composition according to claim 1, wherein said mixture of polysaccharides comprises the monosaccharides galactose, mannose, and glucose in the ratio 1:13.4+/−0.4:12.6+/−1.3.
 5. The composition according to claim 1, wherein every polysaccharide of the composition has a molecular weight of at least 50,000 Da.
 6. The composition according to claim 1, wherein the polysaccharides of said composition comprise the monosaccharides galactose, mannose, and glucose in the ratio 1:7 to 11:2.5 to 3.5.
 7. The composition according to claim 1, wherein the polysaccharides of said composition with a molecular weight in the range of 50,000 to 100,000 Da comprise the monosaccharides galactose, mannose, and glucose in the ratio 1:4 to 14:1 to
 5. 8. The composition according to claim 7, wherein said ratio is approximately 1:8.9:2.9.
 9. The composition according to claim 1, wherein the polysaccharides of said composition with a molecular weight in the range of 100,000 to 300,000 Da comprise the monosaccharides galactose, mannose, and glucose in the ratio 1:3 to 13:1 to
 5. 10. The composition according to claim 9, wherein said ratio is approximately 1:7.3:2.9.
 11. The composition according to claim 1, wherein the polysaccharides of said composition with a molecular weight in the range of 300,000 to 1,000,000 Da comprise the monosaccharides galactose, mannose, and glucose in the ratio 1:5 to 15:1 to
 5. 12. The composition according to claim 11, wherein said ratio is approximately 1:9.9:3.1.
 13. The composition according to claim 1, wherein the polysaccharides of said composition with a molecular weight of more than 1,000,000 Da comprise the monosaccharides galactose, mannose, and glucose in the ratio 1:5 to 15:1 to
 5. 14. The composition according to claim 13, wherein said ratio is approximately 1:10.3:2.9.
 15. The composition according to claim 1, wherein said composition further comprises at least 10 μg/L soluble polypeptide.
 16. The composition according to claim 1, wherein said composition further comprises in the range of 10 to 1000 μg/L soluble polypeptide.
 17. A method of producing a composition according to claim 1, said method comprising the steps of i) cultivating a fungus of the genus Lentinus in a liquid growth medium under appropriate conditions to provide a suitable chemical and physical environment supporting the growth of a fungus of the genus Lentinus in a liquid growth medium, and ii) isolating said composition from said liquid growth medium.
 18. The method according to claim 17, wherein said isolating involves separating polysaccharides with a molecular weight of at least 50,000 Da from other polysaccharides.
 19. The method according to claim 18, wherein said isolating is done by ultracentrifugation, ultrafiltration, microfiltration or gel filtration.
 20. A pharmaceutical composition comprising the composition according to claim 1 and a pharmaceutically acceptable carrier.
 21. A method of treatment of an individual i) diagnosed with an immune compromised condition; and/or ii) at risk of contracting an immune compromised condition; and/or iii) recovering from surgery or illness and at risk of contracting an immune compromised condition; and/or iv) diagnosed with or at risk of contracting acquired immunodeficiency syndrome, said method comprising administering to said individual the composition according to claim 1 in an amount effective in treating or prophylactically treating said immune compromised condition or said syndrome or in boosting the immune system of said individual.
 22. The method according to claim 21, wherein the individual is a mammal.
 23. The composition according to claim 1, wherein the polysaccharides of the composition have a molecular weight of from 50,000 Da to 3,000,000 Da.
 24. The composition according to claim 1, wherein the majority of the polysaccharides of the composition have a molecular weight of at least 50,000 Da.
 25. The composition according to claim 1, further comprising one or more polypeptides.
 26. An aqueous, liquid composition comprising a mixture of polysaccharides, wherein the majority of the polysaccharides of the composition have a molecular weight of at least 1,000,000 Da, wherein essentially no polysaccharides have a molecular weight of less than 1,000,000 Da, wherein said mixture of polysaccharides comprises the monosaccharides galactose, mannose and glucose in the ratio 1:0.033 to 500:1 to 50, and wherein the composition is produced by a method comprising the steps of a) cultivating a fungus of the genus Lentinus in a liquid growth medium under appropriate conditions to provide a suitable chemical and physical environment supporting the growth of a fungus of the genus Lentinus in a liquid growth medium, and b) isolating the composition from said liquid growth medium.
 27. A pharmaceutical composition comprising the composition according to claim 26 and a pharmaceutically acceptable carrier.
 28. A method of treatment of an individual i) diagnosed with an immune compromised condition; and/or ii) at risk of contracting an immune compromised condition; and/or iii) recovering from surgery or illness and at risk of contracting an immune compromised condition; and/or iv) diagnosed with or at risk of contracting acquired immunodeficiency syndrome said method comprising administering to said individual the composition according to claim 26 in an amount effective in treating or prophylactically treating said immune compromised condition or said syndrome or in boosting the immune system of said individual.
 29. The method according to claim 28, wherein the individual is a mammal.
 30. The composition according to claim 1, wherein the majority of the polysaccharides of the composition have a molecular weight in the range of 30,000 Da to 3,000,000 Da.
 31. The composition according to claim 1, wherein the majority of the polysaccharides of the composition have a molecular weight in the range of 50,000 Da to 3,000,000 Da.
 32. The composition according to claim 1, wherein every polysaccharide of the composition has a molecular weight in the range of from 100,000 Da to 3,000,000 Da.
 33. The composition according to claim 1, wherein the polysaccharides of said composition comprise polysaccharides with a molecular weight in the range of from 50,000 to 100,000 Da, polysaccharides with a molecular weight in the range of from 100,000 to 300,000 Da, and polysaccharides with a molecular weight in the range of from 300,000 to 1,000,000 Da.
 34. The composition according to claim 33, wherein the polysaccharides with a molecular weight of from 50,000 to 100,000 comprise the monosaccharides galactose, mannose, and glucose in the ratio 1:4 to 14:1 to
 5. 35. The composition according to claim 34, wherein said ratio is approximately 1:8.9:2.9.
 36. The composition according to claim 33, wherein the polysaccharides with a molecular weight of from 100,000 to 300,000 comprise the monosaccharides galactose, mannose, and glucose in the ratio 1:3 to 13:1 to
 5. 37. The composition according to claim 36, wherein said ratio is approximately 1:7.3:2.9.
 38. The composition according to claim 33, wherein the polysaccharides with a molecular weight of from 300,000 to 1,000,000 comprise the monosaccharides galactose, mannose, and glucose in the ratio 1:5 to 15:1 to
 5. 39. The composition according to claim 38, wherein said ratio is approximately 1:9.9:3.1.
 40. The aqueous, liquid composition according to claim 26, wherein said ratio is 1:5 to 15:1 to
 5. 41. A kit comprising the composition according to claims 1 or 26 and a dosage regime instruction with guidelines for dose and time administration. 